SELECT CORE INTERVALS TO BE SAMPLED.

Either work or archive core halves may be used for smear-slide preparations as samples are minute. The archive half is sometimes preferable as it relates directly to the core photographs in the Geological Collections photo files. For standard core descriptions, sample the top and bottom of the core, each different lithology represented and otherwise at about 100cm intervals. If inspection of smear slides indicates a significant variation of lithology two samples spaced at 100cm, take an intervening sample to better tie down the lithologic change.

ENTER CORE DATA AND SAMPLE INTERVALS ON SMEAR-SLIDE DESCRIPTION SHEET.

Core data includes cruise abbreviation (e.g. CIRCE), core number and coring device (e.g. 4P), cm below top of core (e.g. 133cm). Assume smear slides to be point "intervals" unless a channel sample is taken.

USING A DIAMOND PEN, WRITE CRUISE, CORE NUMBER AND INTERVAL BELOW TOP OF CORE ON GLASS SLIDES.

WASH SLIDES IN IVORY SOAP and blot with paper towels. Do this AFTER data is scratched on slide to remove any glass shards.

DRY SLIDE WITH LINT- FREE, TISSUE (Kimwipes).

LIGHTLY SCRAPE SURFACE OF CORE WITH A METAL SPATULA, at interval selected to remove superficial contamination. (Do not sample immediately adjacent to the core liner as this area is likely to be contaminated or out of place.)

REMOVE MINUTE SAMPLE, THE SIZE OF A PENCIL POINT, FROM THE CORE with a spatula or toothpick. Caution: Some brands of toothpicks can contaminate the sample with wood fibers.

MARK THE SAMPLE LOCATION ON THE VISUAL CORE DESCRIPTION FORM OR DIGITIZED CORE PHOTOGRAPH. It is best to relate a smear-slide or other sample directly to the core photograph to clearly pinpoint the interval or feature from which the sample is taken.

ADD 2 OR 3 DROPS OF DISTILLED WATER TO SEDIMENT ON SLIDE AND SPREAD WITH A SPATULA (or toothpick). Try to maintain a water cushion so that the fragile components are not broken.

PLACE SLIDE ON A HOT PLATE AT MEDIUM HIGH SETTING and allow it to become reasonably hot. (The Norland Adhesive spreads better on a hot slide. If slide gets too hot, however, the slide will break.)

ADD A STRIPE (3 DROPS OR SO) OF NORLAND OPTICAL ADHESIVE AND APPLY COVER SLIP.

For smear slides use small cover slips (2.2 x 3cm). Pond Norland at one end, then tip slide and gently. Ease cover slip over smear trying to avoid bubbles. Coarser-grained smears take more mounting medium than do clays. Try to add just enough medium to fill under the cover slip with a little reservoir (rim of adhesive) outside cover slip. If Norland does not spread to edges of cover slip, add more drops along the edges. Place the cover-slip near the middle of the glass slide so it falls within petrographic-microscope view range and there is room to add more data to the slide, if necessary.

PLACE SLIDE ON SHEET OF PAPER OR CARDBOARD AND SLIDE UNDER ULTRAVIOLET LIGHT SET ON LONG WAVE- LENGTH.

You can feel vibrations or see a faint purplish field below when light is on. Slides need at least a minute to cure, but several minutes under the ultraviolet light will ensure that the medium is firm. A slide can remain under the light for a long period of time without damage. You can put several slides under the ultraviolet ray at a time, but you may need to move them around to get them all exposed. DO NOT LOOK DIRECTLY AT THE ULTRAVIOLET LIGHT. Don't expose skin directly to rays: slide slides under on sheet of paper. Otherwise, the ultraviolet light is said to be safe to operate. Excess Norland can be easily removed with a scalpel.

USE A CLEAN SPATULA TO REMOVE THE NEXT SAMPLE.

      NORLAND OPTICAL ADHESIVE - MOUNTING MEDIUM

Norland Optical Adhesive No. 61 is now used routinely for most smear-slide preparations. Its advantage over Canada Balsam is the speed at which it cures: a few minutes under ultraviolet light as opposed to days in the oven. Handling acetone can also be avoided. Norland cannot be softened upon reheating, however, as can Canada Balsam. Norland is highly suitable for viewing smear-slides in conjunction with core describing. It allows for immediate inspection of components and grain size, yielding quick information about apparent differences in the gross lithology.

Norland No. 61 has a refractive index of 1.560. Microfossil specialists and ODP personnel have reported no degradation within the 10 or so years they have used it. A Norland technical representative claims that within his 20 years of experience he has seen no cases of change in refractive index or increase in opacity of the adhesive.

Keep the Norland adhesive refrigerated. Its shelf life is about 4 months at room temperature but this is considerably extended with refrigeration. The breakdown, however is not in change of optical properties, but in its increased viscosity and reduced adhesive properties.
Norland Optical Adhesive may be ordered from:

Norland Products
695 Joyce Killer Ave, P. O. Box 145
New Brunswick, New Jersey 08902
(732) 545-7828
FAX (732) 545-9542

1999 prices - One 1-oz bottle - $20.00
One box of 12 bottles - $133.92 = $11.16/1-oz

In the past telephone orders were accepted. I understand that the company will now only accept FAXED orders.

(Last revised 3/2002 by pworstell@ucsd.edu)